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Lessons from Hurricane Katrina: A Risk Based Approach to Hospital Evacuation. Chris Johnson Boyd Orr: Julia Appleby, Peter Cooper, Andrew Foss, Stephen Hailey, Benjamin Jenks, Western Infirmary: Fouria Ashraf, Graham McKinlay, Chris McAdam, Jody Johnson, Martin Wilson
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Lessons from Hurricane Katrina:A Risk Based Approach to Hospital Evacuation Chris Johnson Boyd Orr: Julia Appleby, Peter Cooper, Andrew Foss, Stephen Hailey, Benjamin Jenks, Western Infirmary: Fouria Ashraf, Graham McKinlay, Chris McAdam, Jody Johnson, Martin Wilson University of Glasgow, Scotland. http://www.dcs.gla.ac.uk/~johnson
Strathclyde Fire Brigade. BFRL, US NIST.
Hurricane Katrina • Several precursors (Tropical Storm Alison). • East Jefferson General Hospital: • ad hoc evacuations of elderly patients; • waded from emergency department ramp; • elderly care home that was being inundated. • Clinicians and support staff at New Orleans’ University Hospital: • carry patients down 4 flights of stairs; • take them to an improvised ICU when generators flooded. • Chairman of medicine at Tulane University Hospital: • forced to use a colleague’s canoe; • coordinate with New Orleans’ University Hospital and Charity Hospital; • phone lines failed.
Hurricane Katrina • Investigations into multiple fatalities during evacuation of Memorial Medical Center. • Patients on 7th floor carried through hospital. • Many spent considerable time waiting for boat. • Hospital administrator said deaths due to ‘systems failure’. • Criticized lack of guidance on preparation for mass evacuations.
Legislation • International Building Code in 40+ US states - show “construction, size & character of means of egress” and numbers in each space. • OSHA - employers ‘ensure routes leading to exits are accessible and free from materials or items that would impede evacuation’. • UK Fire Precautions (Workplace) Regulations meet EC Directives 89/391 and 89/654 - employers responsible for outcome of adverse event. • Risk-based approach - must demonstrate any precautions are appropriate to the likelihood and consequences of any hazard. • Evacuation measures could be use to demonstrate mitigation of the potential consequences of an adverse event.
2001 Department of Health • “NHS Trusts must have an effective fire safety management system” • They must “ensure emergency evacuation procedures for all areas and undertake fire risk assessments” • Specialist Fire Officers focus on “fire safety audit and fire risk assessments and assisting with reports to management”
But How Do We Do It? • There are few specialist techniques. • Risk assessment for fire: • Only consider evacuation as a mitigating factor? • Can we reason about risk of evacuation hazards? • Legislation is ambiguous in this area… • Slight change in emphasis, focus on evacuation • 1. consider risk of hazards that require evacuation; • 2. consider risks of conducting successful evacuation.
Evacuation of Summerland Bar, Isle of Man: • 51% use the entrance (37 guests, 1 staff member); • - 49% use emergency exit (23 guests, 14 staff).
Woolworths fire in Manchester: - 9 out of the 10 fatalities in canteen; - didnt leave before finishing or paying for meal?
Hospital Fires • Edleman et al (1980) study care home fire. • 95% (85) led down one staircase, 3 others available. • Normal route for staff and patients between floors. • Other 3 were evacuation routes with entry alarms. • Reluctance to use them even when fire justified it. • Evacuation longer than designer & Fire Officers think.
Brooklyn Fire • Fire breaks oxygen hoses treating patient. • Wall outlets now allow free-flow oxygen. • Smoke into hall and patient floor. • Must evacuate many bed-bound patients. • Nurses delay to close area valves: • residual pressure before treatment stops; • Could use back-up bottled oxygen; • But bottles create another fire hazard.
Virginia Fire • 5 die, well designed building, well trained staff. • Less night staff, day staff very busy. • Alarm to fire dept out of service. • Main aim is patient care not fire safety? • Oxygen enriched environment. • Doors wedged open in many wards. • Smoke in ceiling space, fatality distribution. • No sprinkler system also a risk in itself.
Operating Room Fires • Joint Commission on Accreditation of Healthcare Organizations • 100-200 operating room fires each year in US. • Oxygen-enriched environment. • Ignition sources eg lasers and cautery units. • Evacuation risks for patients - ICU sedation. • Train for extinguishers in sterile environments.
Tropical Storm Alison • 3 hospitals close to new patients. • 2 evacuated most critical patients. • 1 hospital completely evacuated. • Shutting down 2000+ beds. • 500+ ICU beds for the City of Houston. • Alison also closed 1 of Houston’s 2 level I trauma hospitals - serves 4 million people.
Lack of Incident Reporting • But no national or Federal registers for these events. • Scots NHS reports fires involving death or serious injury to HSE. • Fires involving death, serious injury or serious damage to Dept of Health. • No information on less serious events or successful evacuations; • 1994-2001 only 6 reports. 5 involved smoking, 1 ‘willful’ fire raising. • Even for serious events, litigation prevents lessons from being learned. • Fire Officers rely on ‘war stories’, word of mouth in meetings and exercises. • Contrast with legal reporting requirements for device failure in healthcare.
US Hospital Fire Drills • 3 mock fire drills during a 6-week period. • Electrosurgical pencil ignites drape. • Staff remove cover from patient, • throw onto floor, use extinguisher. • Organisers then say fire spread. • Simulate move of intubated patients • OR bed with a bag-valve mask. • Pack wounds with sterile sponges; • e.g. don’t move anaesthesia machine. • Gridlock, rooms evacuate at same time.
US Hospital Fire Drills • Debrief sessions especially if problems. • poor emergency response checklist; • delays in backup if patient and anaesthetist ‘injured’ in exercise. • Anaesthetist evacuate by OR back door: • steep incline above a busy road; • Hospital posts signs on doors. • ‘Systemic’ problems: • hospital paging coordinates response; • announcements could not be heard; • staff leave posts to check; • No plans if it were damaged; • messenger post opened & buy radios.
Horizontal Evacuation • Does movement create greater risks than hazard? • Check location of fire, secure refuge & exit route: • Refuges within 12 meters of each patient’s room; • 70 secs to move patient to place of safety; • 30 secs more for staff to return to patient’s room. • Patients in immediate danger moved first. • Non-ambulatory before mobile patient & visitors; • Wheelchair patients grouped together ; • Staff lead mobile patients in a single journey. • Patients must not impede emergency personnel. • 3 people, 5 mins to disconnect/reconnect units; • 15 mins, conscious patient bed to wheelchair.
But… • Wisconsin urges staff not to use ‘horizontal’ evacuation: • evacuations should move all patients outside the building; • ‘required, regardless of building construction’; • ‘may not use defend in place methodologies’ drills too; • use of patients in drills is optional. • Department of Health in Scotland: • “less annual fire training if risk assessment carried out”; • “fire safety training appropriate to duties of the staff”; • “at least annually for staff involved in patient evacuation”.
Limitations of Drills • Sustained Costs. • Limited Accuracy. • Short ‘Shelf Life’. • Lack of Design Focus. • Danger. • Poor Reliability.
Crowd Density and Velocity Thompson and Marchant (1995)
Simulation results: • over 20 runs; • Blocking exits; • Lower figures are SDs.
Faster evacuation under model conditions: • North exit closed and a long way to main exit; • BUT only one bottleneck/door to main exit.
Modelling Nurse Behaviour • Coding of nursing staff behavior based on concurrent threads. • program creates an independent process for each individual. • Communication through a form of message passing; • Reactive route finding for each nurse using A* algorithm: • Simulated nurse ranks each possible moves from their current location; • Only go on to consider the next set of available moves from the top ranked adjacent position; • planned route gradually grows by always picking best next step for further consideration; • if potential route blocked then consider second route in the list of preferences. • Algorithm depends on appropriate heuristic: • Euclidian distance or detailed information about hospital layout; • Recall: • nurses modeled as independent threads and • each uses own independent navigation strategy; • contention will occur if 2 nurses move 2 beds along narrow corridor. • Specialist negotiation algorithms needed to resolve bottleneck.
Simplifying Assumptions • Timings for equipment on one floor of a particular hospital. • No obstacles – is this likely in a busy ward? • Bed movement did not require complex rotations for sharp corners. • Beds movements depends on model and maintenance provided: • Beds approx. 1 meter (38 inches) by 2.2 metres (86 inches). • Wheelchairs 0.75 metres (30 inches) by 0.75 metres (30 inches). • However, there were several different models. • Some wheelchairs upholstered similar to a moveable armchair. • others were based around more conventional metal frames. • No smoke, no cumulative fatigue effects etc.
Further Work • RPDN on evacuation response. • Emergency ingress not just egress.
Questions? Thanks are due to Julia Appleby, Peter Cooper, Andrew Foss, Stephen Hailey, Benjamin Jenks, Fouria Ashraf, Graham McKinlay, Chris McAdam, Jody Johnson, Martin Wilson...